[vsnet-grb-info 16535] GRB 150514A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17816
SUBJECT: GRB 150514A: Fermi-LAT detection  
DATE:    15/05/15 04:56:37 GMT
FROM:    Daniel Kocevski at GSFC  <daniel.kocevski at nasa.gov>

D. Kocevski (NASA/GSFC) and M. Arimoto (Tokyo Tech),
report on behalf of the Fermi-LAT team:

At 18:35:05.35 on May 14, 2015, Fermi-LAT detected high-energy emission from GRB 150514A, which was also detected by Fermi-GBM (trigger 453321308).

The best LAT on-ground location is found to be

RA, Dec = 74.85, -60.91 (J2000)

with an error radius of 0.12 deg (90% containment, statistical error only). This position was 40 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The LAT localization relies heavily on the detection of a single 6.5 GeV event at T0 + 400s, roughly 2.2 deg from the final GBM position. The GRB was observable from T0 to T0 + 600 s, before the spacecraft entered the South Atlantic Anomaly, where data gathering is disabled.

The Fermi-LAT point of contact for this burst is Makoto Arimoto (arimoto at hp.phys.titech.ac.jp<mailto:arimoto at hp.phys.titech.ac.jp>).

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.